Premium
Mechanistic Aspects of Charge‐remote Fragmentation in Saturated and Mono‐unsaturated Fatty Acid Derivatives. Evidence for Homolytic Cleavage
Author(s) -
Claeys Magda,
Nizigiyimana Libérata,
Van den Heuvel Hilde,
Derrick Peter J.
Publication year - 1996
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/(sici)1097-0231(199605)10:7<770::aid-rcm575>3.0.co;2-d
Subject(s) - chemistry , allylic rearrangement , fragmentation (computing) , homolysis , dissociation (chemistry) , cleavage (geology) , ion , collision induced dissociation , medicinal chemistry , photochemistry , oleic acid , stereochemistry , organic chemistry , mass spectrometry , radical , tandem mass spectrometry , catalysis , chromatography , biochemistry , geotechnical engineering , fracture (geology) , computer science , engineering , operating system
The high‐energy collision‐induced dissociation (CID) of [M+Li] + ions of n ‐butyl ester derivatives of palmitic acid and oleic acid as well as 9,9‐ 2 H 2 ‐palmitic acid and 11,11‐ 2 H 2 ‐oleic acid has been studied in order to obtain information on the charge‐remote fragmentation mechanism of saturated and mono‐unsaturated fatty acid ions containing a stable charge centre. The results obtained in the present study indicate that homolytic cleavage reactions, involving C—H cleavage as an initial rate‐determining step, operate during the charge‐remote fragmentation observed for high‐energy CID of [M+Li] + ions of n ‐butyl palmitate and correspond to a major fragmentation route. With respect to the charge‐remote fragmentation of n ‐butyl oleate, our 2 H‐labelling results point to the same mechanism, involving an initial C—H cleavage at allylic positions, for the formations of ions corresponding to a formal homo‐allylic cleavage, and are also consistent with a direct allylic C—C cleavage for the formation of ions due to a formal allylic C—C cleavage. These results, however, do not exclude the possibility of other minor homolytic fragmentation pathways for the formation of ions involving formal allylic and homo‐allylic cleavages.